I believe Charley Lillard had a documented '69 Z once where the original owner ordered the MA6 and it wasn't built with that option. Not sure if that means it was never actually available or if it just was not available at the time the car actually got built.

The heavy duty dual disc clutch RPO W37 was offered by Oldsmobile in 71 & 72. In 71 it only required the M20 or M22 option & 442, but in 72 they made it engine specific with the L75 & L77 engines in any model of Cutlass with the M20 trans.............RatPack..................